In a known tube type irrigation system, a plurality of tubes with many bores directed upwards at an angle, through which the acid is discharged radially, extend from a main distributor tube. By means of baffle plates attached to the tubes these jets are directed downwards into the packed bed.
Such systems are used, for instance, for the countercurrent absorption of SO3 or water vapor in sulfuric acid in a packed tower. In the head of an, for example, cylindrical container, the absorber acid is uniformly distributed over the apparatus cross-section by means of an irrigation system and trickles through a packed bed from the top to the bottom. From the gas countercurrently flowing to the top, the trickling acid absorbs the SO3, with the acid concentration rising correspondingly, or water, whereby the acid is diluted. In standard configurations, the absorber constitutes a packed tower constructed as a counterflow apparatus, whose shell is divided into three zones: the lower part is formed by the sump with the acid outlet, the middle part contains, for instance, the packed bed on a support grid through which the acid, which is uniformly distributed by an irrigation system located on top of the bed, trickles downwards. The acid inlet to the irrigation system and the gas outlet are located above the packed bed. Known issues of such systems are the reduced gas outlet area, which leads to an undesired local increase in the gas velocity and, hence, promotes the entrainment of acid droplets or mists.
US 2004/0182013 A1 describes a distributor system in which the fluid is discharged pressureless from a plurality of openings in the side wall of a distributor trough open at the top and is guided to a lower dripping edge by means of a laterally downwardly curved mesh structure, wherein the mesh structure is passed through a distributor channel forming a throttle. This device on the one hand involves the problem of the entrainment of fine acid droplets and mists, and on the other hand the individual distributor members consisting of distributor trough and mesh structure have an undesirably high space requirement, which leads to a reduction of the area available for the gas flow.
U.S. Pat. No. 5,906,773 A describes a liquid distributor system in which the liquid is guided from a distributor trough which in a wall includes two openings arranged one above the other at a distance and leading into a vertical guiding tube, onto an inclined baffle surface 5 on which a weir is formed which should promote the further distribution of the liquid. The liquid then flows via a vertical guiding plate 7 onto the surface of the filler packing. Apart from the space requirement of these distributor members, there is also the problem of the entrainment of liquid droplets or mists.
A similar configuration of a counterflow column is described in U.S. Pat. No. 6,575,437 B2, in which the liquid is passed onto the packing as a film and without pressure via a baffle plate arranged laterally with respect to a distributor trough.
U.S. Pat. No. 5,439,620 A describes distributor tubes in which liquid emerges from openings in the upper surface thereof and flows via guiding surfaces provided laterally at the distributor tubes, which have a serrated dripping edge, up to the surface of the packing. The desired uniform distribution of the liquid alone the length of the distributor tubes is not positively ensured. Another issue here is the exact control of the pressure to avoid splashing of liquid from the opening.